Odd, I wondered why you weren't posting, I guess I just missed your missing thread.
Anyway, it is a tough road to follow, not being too available, not pursuing, yet not closing the door on your M. It sounds like you may be pushing W away.
Has she been initiating invites all along? If so, nevermind.
If not, notice that you turned her down twice in a row. Did you give her anything other than "no, I have plans"? I'm not suggesting that you should have changed your plans, but maybe: "that would have been nice, give me some warning next time so I can clear my schedule."
Keep in mind that it might be very hard for W to muster the courage if she is trying to reach toward you.
OTOH, don't let expectations go to your head. Many times, a WAS simply wants to be friends and has the space to do so once you let go. So, don't read too much into it.
